I started by test fitting the original cannon barrel PVC schedule 40 components. The cardboard tube is a Lava Lamp's packaging. The cannon balls are yellow foam practice golf balls from the local department store. I took one to the hardware store and found that it fit snugly inside a 1.5" PVC tube. The 'T' fitting has a 1" leg that I fit an additional reducer into it that accepted the knurled brass fitting for the rubber air supply tube.